The present invention relates to a process for manufacturing a semiconductor integrated circuit device and, more particularly, to a technique which is effective when applied to a gas-phase treating process for a semiconductor wafer using a hydrogen gas.
In a semiconductor manufacturing process, it is known to use a hydrogen-annealing treatment for feeding hydrogen to a polycrystalline silicon film for constructing the gate electrodes of a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) and a Si (silicon) substrate. For this hydrogen annealing treatment, the hydrogen gas is introduced into a batch type or sheet type hydrogen-annealing furnace housing a semiconductor wafer to heat-treat this semiconductor wafer. in a hydrogen atmosphere at about 400xc2x0. After this hydrogen-annealing treatment, the trap level, as caused by the dangling bonds (or uncoupled bonds) of Si, is terminated by the hydrogen so that the characteristics of the MOSFET are improved.
In the prior art, the hydrogen gas, as discharged from the hydrogen-annealing furnace, is eliminated by a combustion method. In this regard, air is introduced into the exhaust line of the hydrogen-annealing apparatus to burn and convert the hydrogen into water by the spark ignition method. In a hydrogen-annealing furnace of a relatively small scale, on the other hand, the discharged hydrogen may be diluted with a large amount of nitrogen gas or air and released to the atmosphere.
In a process for forming MOSFETs over a Si substrate, on the other hand, the Si substrate is wet-oxidized to form a gate oxide film on its surface. For this formation, there is also utilized a combustion method, in which water is generated by burning hydrogen in an oxygen atmosphere and the water is fed together with the oxygen to the surface of the semiconductor wafer.
For generating a water/hydrogen mixed gas to wet-oxide the Si substrate, a catalytic method is well known in the art in addition to 25, the combustion method. For example, Japanese Patent Laid-Open No. 5-152282/1993 (hereinafter to be called xe2x80x9cOhmixe2x80x9d) has disclosed a thermal oxidizing apparatus in which a hydrogen gas inlet pipe is made at its inner face of Ni (nickel) or a Ni-containing material and which is equipped with means for heating the hydrogen gas inlet pipe. This thermal oxidizing apparatus generates water by bringing the hydrogen into contact with the Ni (or Ni-containing material) in the hydrogen gas inlet pipe heated to 300xc2x0 C. or higher, to generate hydrogen activated species and by causing these hydrogen activated species and the oxygen (or the gas containing oxygen) to react with each other.
In a process for forming gate electrodes over the gate oxide film thus formed by the wet-oxidizing method, moreover, the gate electrode material, as deposited on the gate oxide film, is patterned by a dry-etching method. After this, the photoresist employed as the etching mask is eliminated by aching treatment, and the dry-etching residue or aching residue, as left on the surface of the substrate, is eliminated by an etching liquid, such as hydrofluoric acid.
With this wet-etching treatment, the gate oxide film is etched off not only from regions other than those under the gate electrodes, but also isotropically from the end portions of the side walls of the gate electrodes, thereby to cause an under-cut. This under-cut will cause, as it is, a defect in the form of a drop in the withstand voltage of the gate electrodes. In order to improve the profile of the under-cut end portions of the side walls of the gate electrodes, therefore, a so-called xe2x80x9clight oxidation treatmentxe2x80x9d is performed to thermally oxidize the substrate again, thereby to form an oxide film on its surface.
If, however, the light oxidation treatment is applied to the gate electrodes of the poly-metal structure, which contains a refractory metal, such as W (tungsten) or Mo (molybdenum), that is liable to be oxidized in a hot oxygen atmosphere, the refractory metal film is oxidized to raise its resistance or is partially separated from the substrate. For a gate treating process using a poly-metal, therefore, there are required counter-measures for preventing the refractory metal film from being oxidized during the light oxidation treatment.
Japanese Patent Laid-Open No. 59-132136/1984 (hereinafter to be called xe2x80x9cKobayashixe2x80x9d) has disclosed a technique for oxidizing Si selectively, but not a W (or Mo) film, by light-oxidizing the gate electrodes of the poly-metal structure including the W film or the Mo film over the Si substrate, in a mixed atmosphere of steam and hydrogen.
This technique utilizes the fact that the partial pressure ratio of steam/hydrogen for balancing the oxidizing/reducing reactions is different between W (Mo) and Si. The selective oxidation of Si is realized by setting the partial pressure ratio within a range wherein the W (Mo) may be oxidized with steam, but quickly reduced with the coexisting hydrogen, whereas the Si may be left oxidized. On the other hand, the steam/hydrogen mixed atmosphere is generated by the bubbling method of feeding the hydrogen gas to pure water contained in a container, and the steam/hydrogen partial pressure ratio is controlled by changing the temperature of the pure water.
In the light oxidation process, as disclosed, the Si substrate is oxidized with the steam/hydrogen mixed gas so that the hydrogen gas is contained in the exhaust gas discharged from the oxidizing furnace. In this case, too, there are required some counter-measures for eliminating the hydrogen gas from the exhaust gas.
Another well-known exhaust gas eliminating method, as employed in the semiconductor manufacturing process, is disclosed in Japanese Patent Laid-Open No. 8-83772/1996 (hereinafter to be called xe2x80x9cWatanabexe2x80x9d). In this method, an exhaust gas containing tetraethoxysilane discharged from a CVD (Chemical Vapor Deposition) apparatus is guided into an adsorption tower to come into contact with a metal oxide catalyst (or an adsorbent carrying the catalyst) so that it may be oxidized and decomposed into a powder of silicon dioxide and diethyl ether. The metal oxide catalyst to be employed is exemplified by NiO, CuO, Mn2O3 or Fe2O3.
Moreover, Japanese Patent Laid-Open No. 9-75651/1997 (hereinafter to be called xe2x80x9cKoyashikixe2x80x9d) has disclosed a method in which a silane gas is eliminated as the powder of silicon dioxide by mixing and oxidizing an (water-soluble) ammonium gas and the silane gas with oxygen, in which the ammonia gas is eliminated by rinsing and in which the remaining noxious gases are adsorbed and eliminated with active carbon.
According to our investigations, in the aforementioned hydrogen-annealing process for a semiconductor wafer, the hydrogen gas to be discharged from a hydrogen-annealing furnace has to be ignited, after sufficient air was fed to the exhaust line, so that it may be eliminated by the combustion method. As a result, the flame is liable to go out when the supply of hydrogen gas becomes short, such as at the time of switching between the hydrogen gas and the purge gas, and the unburned hydrogen is discharged as it is to the outside. Since the hydrogen-annealing treatment is performed at a temperature as high as about 400xc2x0 C., however, the amount of the unburned hydrogen in the hot exhaust gas may lead to the danger of explosion. Moreover, this hydrogen eliminating method by the use of combustion poses another problem in that the scale of the eliminator is enlarged.
On the other hand, the elimination method involving a diluting of the hydrogen gas, as discharged from the hydrogen-annealing furnace, with a large amount of nitrogen gas or air and discharging it to the atmosphere employs much diluting gas because the hydrogen gas concentration has to be lowered to about several percent for safety. This elimination method, like the combustion method, poses the problem that the scale of the eliminator is enlarged, and therefore is not suitable for eliminating a large amount of hydrogen gas.
Moreover, the method of Koyashiki using an adsorbent, such as active carbon, is environmentally defective because it will not convert a noxious substance into a safe one.
On the other hand, the method of Watanabe, which generates a powdery product which is troublesome to handle or a highly flammable substance, such as diethyl ether, is liable to cause problems if applied to a mass-production process.
An object of the invention is to provide a technique which, in a process for gas-phase treating a semiconductor wafer with a treating gas containing hydrogen, can eliminate the hydrogen safely from exhaust gas discharged from a gas-phase treating apparatus.
Another object of the invention is to provide a technique which, in a process for gas-phase treating a semiconductor wafer with a treating gas containing hydrogen, can eliminate the hydrogen efficiently from exhaust gas discharged from a gas phase treating apparatus.
The aforementioned and other objects and novel features of the invention will become apparent from the description to be made with reference to the accompanying drawings.
Representative features of the invention to be disclosed herein will be briefly summarized in the following.
(1) A process for manufacturing a semiconductor integrated circuit device according to the invention comprises: the step of gas-phase treating a semiconductor wafer with a treating gas containing hydrogen; and the step of eliminating the hydrogen, as contained in the gas-phase treated exhaust gas, by causing the hydrogen to react with oxygen by using a catalyst.
(2) In a semiconductor integrated circuit device manufacturing process of the invention, a hydrogen eliminator for eliminating the hydrogen contained in said exhaust gas is disposed in an exhaust line of a gas-phase treating device for gas-phase treating said semiconductor wafer.
(3) In a semiconductor integrated circuit device manufacturing process of the invention, said hydrogen eliminator is disposed at each exhaust line of said gas-phase treating unit.
(4) In a semiconductor integrated circuit device manufacturing process of the invention, one said hydrogen eliminator is disposed at the exhaust lines of a plurality of said gas-phase treating units.
(5) In a semiconductor integrated circuit device manufacturing process of the invention, the treatment of eliminating the hydrogen contained in said exhaust gas is performed by a single wafer process or a batch process.
(6) A process for manufacturing a semiconductor integrated circuit device according to the invention comprises: the step of forming gate electrodes of a MOSFET by depositing a conductive film containing at least a metal film on a gate oxide film formed over the principal face of a semiconductor substrate and by patterning said conductive film; the step of improving the profile of the end portions of the side walls of said gate electrodes by feeding a hydrogen gas containing steam, as generated from hydrogen and oxygen by catalytic action, to the principal face or the vicinity of said semiconductor substrate which is heated to a predetermined temperature, thereby to oxidize the principal face of said semiconductor substrate selectively; and the step of eliminating the hydrogen, as contained in the oxidized exhaust gas, by causing it to react with oxygen by using a catalyst.
(7) In a semiconductor integrated circuit device manufacturing process of the invention, the steam/hydrogen partial pressure ratio of the hydrogen gas containing said steam is set within such a range that said metal film may be reduced, whereas the principal face of said semiconductor substrate may be oxidized.
(8) In a semiconductor integrated circuit device manufacturing process of the invention, said conductive film includes at least a Ti film, and the principal face of said semiconductor substrate is selectively oxidized with the hydrogen gas containing steam of such a low concentration that the deterioration of said gate electrodes by the oxidation of said Ti film may be minimized.
(9) In a semiconductor integrated circuit device manufacturing process of the invention, said conductive film includes at least a W film, and the principal face of said semiconductor substrate is selectively oxidized with the hydrogen gas containing steam of such a low concentration as to be able to control the oxidation rate and the oxidized film thickness.
(10) In a semiconductor integrated circuit device manufacturing process of the invention, the conductive film constructing said gate electrodes includes a polycrystalline silicon film, a metal nitride film deposited on said polycrystalline silicon film, and a metal film deposited on said metal nitride film.
(11) In a semiconductor integrated circuit device manufacturing process of the invention, said metal nitride film is made of WN or TiN, and said metal film is made of W, Mo or Ti.
(12) A process for manufacturing a semiconductor integrated circuit device according to the invention comprises: the step of forming gate electrodes of a MOSFET by depositing a conductive film including at least a metal film over a gate oxide film having a thickness of 5 nm or less and formed over the principal face of a semiconductor substrate and then by patterning said conductive film; the step of improving the profile of the end portions of the side walls of said gate electrodes by oxidizing the principal face of said semiconductor substrate selectively by feeding the hydrogen gas containing steam of such a low concentration, as is generated from hydrogen and oxygen by catalytic action and can control the reproductivity of the oxide film formation and the homogeneity of the oxide film thickness, to the principal face or the vicinity of said semiconductor substrate heated to a predetermined temperature, thereby to oxidize the principal face of said semiconductor substrate selectively; and the step of eliminating the hydrogen, as contained in the oxidized exhaust gas, by causing it to react with oxygen by using a catalyst.
(13) A process for manufacturing a semiconductor integrated circuit device according to the invention comprises: the step of forming one or more layers of wiring over the principal face of a semiconductor substrate and then depositing a passivation film on the wiring of the uppermost layer; the step of terminating the dangling bonds of Si with hydrogen by heat treating said semiconductor substrate in a gas atmosphere containing hydrogen in the course of or before or after the step of depositing said passivation film; and the step of eliminating the hydrogen, as contained in the heat treated exhaust gas, by causing it to react with oxygen by using a catalyst.
The remaining aspects of the invention will be itemized and briefly described in the following.
1. A process for manufacturing semiconductor integrated circuit device, comprising:
(a) the step of treating a semiconductor integrated circuit wafer, as housed in a reaction furnace, in a gas atmosphere containing a hydrogen gas;
(b) the step of discharging said gas atmosphere to the outside of said reaction furnace; and
(c) the-step of converting the hydrogen gas, as contained in said atmosphere, into water by treating said discharged gas atmosphere with an oxidizing catalyst.
2. A process for manufacturing semiconductor integrated circuit device, comprising:
(a) the step of treating a semiconductor integrated circuit wafer, as housed in a reaction furnace, in a gas atmosphere containing a combustible gas;
(b) the step of discharging said gas atmosphere to the outside of said reaction furnace; and
(c) the step of converting the said combustible gas, as contained in said atmosphere, into at least one non-combustible component exclusively by treating said discharged gas atmosphere with an oxidizing catalyst.
3. A process for manufacturing semiconductor integrated circuit device, comprising:
(a) the step of treating a semiconductor integrated circuit wafer, as housed in a reaction furnace, with a gas atmosphere containing a combustible gas and steam synthesized by using a catalyst;
(b) the step of discharging said gas atmosphere to the outside of said reaction furnace; and
(c) the step of converting the said combustible gas, as contained in said atmosphere, into at least one non-combustible component exclusively by treating said discharged gas atmosphere with an oxidizing catalyst.
4. A process for manufacturing semiconductor integrated circuit device, comprising:
(a) the step of thermally oxidizing a first region containing silicon as its major component selectively by heat treating a semiconductor integrated circuit wafer, which has said first region and a second region containing a refractory metal but not silicon as its major component, in a reaction furnace in a gas atmosphere containing a hydrogen gas and steam;
(b) the step of discharging said gas atmosphere to the outside of said reaction furnace; and
(c) the step of converting the hydrogen gas, as contained in said atmosphere, into water by treating said discharged gas atmosphere with an oxidizing catalyst.
5. A process for manufacturing semiconductor integrated circuit device, comprising:
(a) the step of thermally oxidizing a first region selectively by heat treating a semiconductor integrated circuit wafer, which has said first region and a second region made of a material different from that of said first region, in a reaction furnace in a gas atmosphere containing a hydrogen gas and steam;
(b) the step of discharging said gas atmosphere to the outside of said reaction furnace; and
(c) the step of converting the hydrogen gas, as contained in said atmosphere, into water by treating said discharged gas atmosphere with an oxidizing catalyst.
6. A process for manufacturing semiconductor integrated circuit device, comprising:
(a) the step of treating a semiconductor integrated circuit wafer, as housed in a reaction furnace, in a gas atmosphere containing a combustible gas;
(b) the step of discharging said gas atmosphere to the outside of said reaction furnace; and
(c) the step of converting the said combustible gas, as contained in said atmosphere, into at least one non-combustible component exclusively by treating said discharged gas atmosphere with an oxidizing catalyst in a catalytic treating chamber disposed in the vicinity of said reaction furnace.
7. A process for manufacturing a semiconductor integrated circuit device, comprising:
(a) the step of forming a poly-silicon film over a gate insulating film including a silicon oxide film formed on the silicon surface of a semiconductor wafer;
(b) the step of forming a refractory metal film containing tungsten as its major component directly or through a barrier layer over said poly-silicon film;
(c) the step of forming gate electrodes by patterning said poly-silicon film and said refractory metal film;
(d) the step of thermally oxidizing, additionally after said step (c), the silicon and poly-silicon portions in a mixed atmosphere containing a hydrogen gas and steam synthesized with a catalyst from oxygen and a hydrogen gas;
(e) the step of discharging said mixed atmosphere to the outside of said thermally oxidizing region; and
(f) the step of converting the hydrogen gas, as contained in said mixed atmosphere, into water by treating said discharged gas atmosphere with an oxidizing catalyst.
8. A process for manufacturing a semiconductor integrated circuit device, comprising:
(a) the step of forming a poly-silicon film over a gate insulating film including a silicon oxide film formed on the silicon surface of a semiconductor wafer;
(b) the step of forming a refractory metal film directly or through a barrier layer over said polysilicon film;
(c) the step of forming gate electrodes by patterning said poly-silicon film and said refractory metal film;
(d) the step of thermally oxidizing, additionally after said step (c), the silicon and poly-silicon portions in a mixed atmosphere containing a hydrogen gas and steam synthesized with use of a catalyst from oxygen and a hydrogen gas;
(e) the step of discharging said mixed atmosphere to the outside of said thermally oxidizing region; and
(f) the step of converting the hydrogen gas, as contained in said mixed atmosphere, into water by treating said discharged gas atmosphere with an oxidizing catalyst.
9. A process for manufacturing semiconductor integrated circuit device, comprising:
(a) the step of heat treating a first region over a semiconductor wafer and a second region made of a material different from that of said first region in a mixed atmosphere containing a hydrogen gas and steam synthesized from oxygen and a hydrogen gas with use of a catalyst, so that said first region may be oxidized whereas said second region may not be substantially oxidized;
(b) the step of discharging said mixed atmosphere to the outside of said thermally oxidizing region; and
(c) the step of converting the hydrogen gas, as contained in said atmosphere, into water by treating said discharged gas atmosphere with an oxidizing catalyst.
10. A process for manufacturing a semiconductor integrated circuit device, comprising:
(a) the step of forming a first film containing silicon as a major component over a gate insulating film including a silicon oxide film formed on the silicon surface of a semiconductor wafer;
(b) the step of forming a refractory metal film directly or through a barrier layer over said first film;
(c) the step of forming gate electrodes by patterning said first film and said refractory metal film;
(d) the step of thermally oxidizing, additionally after said step (c), the silicon and poly-silicon portions in a mixed atmosphere containing a hydrogen gas and steam synthesized with use of a catalyst from oxygen and a hydrogen gas;
(e) the step of discharging said mixed atmosphere to the outside of said thermally oxidizing region; and
(f) the step of converting the hydrogen gas, as contained in said mixed atmosphere, into water by treating said discharged gas atmosphere with an oxidizing catalyst.
11. A process for manufacturing a semiconductor integrated circuit device, comprising:
(a) the step of forming element isolating grooves in the silicon surface of a semiconductor integrated circuit;
(b) the step of burying members from the outside in said element isolating grooves;
(c) the step of flattening said wafer surface, after said step (b), by a chemical mechanical polishing method;
(d) the step of forming a poly-silicon film over a gate insulating film containing a silicon oxide film formed on the silicon surface of said semiconductor wafer;
(e) the step of forming a refractory metal film directly or through a barrier layer over said polysilicon film;
(f) the step of forming gate films by patterning said poly-silicon film and said refractory metal film;
(g) the step of thermally oxidizing, after said step (f), the silicon and poly-silicon portions in a mixed atmosphere containing a hydrogen gas and steam so that said refractory metal film may not be substantially oxidized;
(h) the step of discharging said mixed atmosphere to the outside of said thermally oxidizing region; and
(i) the step of converting the hydrogen gas, as contained in said mixed atmosphere, into water by treating said discharged gas atmosphere with use of an oxidizing catalyst.
12. A process for manufacturing a CMOS semiconductor integrated circuit device, comprising:
(a) the step of forming a poly-silicon film over a gate insulating film containing a silicon oxide film formed on the silicon surface of a semiconductor wafer;
(b) the step of forming a refractory metal film containing tungsten as a major component through a barrier layer containing a tungsten nitride film over said poly-silicon film;
(c) the step of forming gate films by patterning said poly-silicon film and said refractory metal film;
(d) the step of thermally oxidizing, after said step (c), the silicon and poly-silicon portions in a mixed atmosphere containing a hydrogen gas and steam so that said refractory metal film may not be substantially oxidized;
(e) the step of discharging said mixed atmosphere to the outside of said thermally oxidizing region; and
(f) the step of converting the hydrogen gas, as contained in said mixed atmosphere, into water by treating said discharged gas atmosphere with use of an oxidizing catalyst.
13. A process for manufacturing a CMOS semiconductor integrated circuit device, comprising:
(a) the step of forming a poly-silicon film over a gate insulating film containing a silicon oxide film formed on the silicon surface of a semiconductor wafer;
(b) the step of forming a refractory metal film containing tungsten as a major component through a barrier layer containing a tungsten nitride film over said poly-silicon film;
(c) the step of forming gate electrodes by patterning said poly-silicon film and said refractory metal film;
(d) the step of thermally oxidizing, after said step (c), the silicon and poly-silicon portions in a mixed atmosphere of a gas for oxidizing and reducing the silicon and the poly-silicon so that said refractory metal film may not be substantially oxidized;
(e) the step of discharging said mixed atmosphere to the outside of said thermally oxidizing region; and
(f) the step of converting said mixed atmosphere into a non-combustible atmosphere by treating said discharged gas atmosphere with use of an oxidizing catalyst.
14. A process for manufacturing a semiconductor integrated circuit device, comprising:
(a) the step of forming a poly-silicon film over a gate insulating film containing a silicon oxide film formed on the silicon surface of a semiconductor wafer;
(b) the step of forming a refractory metal film containing tungsten as a major component directly or through a barrier layer over said poly-silicon film;
(c) the step of forming gate electrode by patterning said poly-silicon film and said refractory metal film;
(d) the step of thermally oxidizing, additionally after said step (c), the silicon and poly-silicon portions in a mixed atmosphere of a gas for reducing the silicon and the poly-silicon and an oxidizing gas, as synthesized with use of an oxidizing catalyst, so that said refractory metal film may not be substantially oxidized;
(e) the step of discharging said mixed atmosphere to the outside of said thermally oxidizing region; and
(f) the step of converting said mixed atmosphere into a non-combustible atmosphere by treating said discharged gas atmosphere with use of an oxidizing catalyst.
15. A process for manufacturing semiconductor integrated circuit device, comprising:
(a) the step of hydrogen-annealing a semiconductor integrated circuit wafer having a final passivation film, in a reaction furnace in a gas atmosphere containing a hydrogen gas;
(b) the step of discharging said gas atmosphere to the outside of said reaction furnace; and
(c) the step of converting the hydrogen gas, as contained in said atmosphere, into water by treating said discharged gas atmosphere with an oxidizing catalyst.
16. A process for manufacturing semiconductor integrated circuit device, comprising:
(a) the step of heat treating a semiconductor integrated circuit wafer in a reaction furnace in a gas atmosphere containing a hydrogen gas and steam;
(b) the step of discharging said gas atmosphere to the outside of said reaction furnace; and
(c) the step of converting the hydrogen gas, as contained in said atmosphere, into water by treating said discharged gas atmosphere with use of an oxidizing catalyst.
17. A semiconductor integrated circuit device manufacturing process according to claim 16,
wherein said wafer is a silicon wafer prepared by the Czochralski method.
18. A semiconductor integrated circuit device manufacturing process according to claim 17,
wherein said wafer is a wafer having a silicon epitaxial layer over a silicon substrate.
19. A semiconductor integrated circuit device manufacturing process according to claim 18,
wherein said wafer is a wafer having a silicon epitaxial layer over a silicon substrate.
20. A semiconductor integrated circuit device manufacturing process according to claim 19,
wherein the treatment with said catalyst is performed in a non-combustible temperature region of hydrogen.
21. A semiconductor integrated circuit device manufacturing process according to claim 20,
wherein the feed and discharge of said atmosphere are performed either substantially simultaneously or continuously with the heat treatment.
22. A semiconductor integrated circuit device manufacturing process according to claim 21,
wherein said heat treatment is performed in a temperature region of 700xc2x0 C. or higher.
Moreover, the foregoing and other features will be itemized and briefly described from other aspects.
23. A process for manufacturing a semiconductor integrated circuit device comprises: the step of gas phase treating a semiconductor wafer with a treating gas containing hydrogen; and the step of eliminating the hydrogen, as contained in the gas-phase treated exhaust gas, by causing the hydrogen to react with oxygen by use of a catalyst.
24. In a semiconductor integrated circuit device manufacturing process as set forth in item 23, a hydrogen eliminator for eliminating the hydrogen contained in said exhaust gas is disposed in an exhaust line of a gas-phase treating device for gas phase treating said semiconductor wafer.
25. In a semiconductor integrated circuit device manufacturing process as set forth in item 24, said hydrogen eliminator is disposed at each exhaust line of said gas-phase treating unit.
26. In a semiconductor integrated circuit device manufacturing process as set forth in item 24, one said hydrogen eliminator is disposed at the exhaust lines of a plurality of said gas-phase treating units.
27. In a semiconductor integrated circuit device manufacturing process as set forth in item 23, the treatment of eliminating the hydrogen contained in said exhaust gas is performed by a single wafer process or a batch process.
28. A process for manufacturing a semiconductor integrated circuit device comprises: the step of forming gate electrodes of a MOSFET by depositing a conductive film containing at least a metal film on a gate oxide film formed over the principal face of a semiconductor substrate and by patterning said conductive film; the step of improving the profile of the end portions of the side walls of said gate electrodes by feeding a hydrogen gas containing steam, as generated from hydrogen and oxygen by catalytic action, to the principal face or the vicinity of said semiconductor substrate which is heated to a predetermined temperature, thereby to oxidize the principal face of said semiconductor substrate selectively; and the step of eliminating the hydrogen, as contained in the oxidized exhaust gas, by causing it to react with oxygen by use of a catalyst.
29. In a semiconductor integrated circuit device manufacturing process as set forth in item 28, the steam/hydrogen partial pressure ratio of the hydrogen gas containing said steam is set within such a range that said metal film may be reduced whereas the principal face of said semiconductor substrate may be oxidized.
30. In a semiconductor integrated circuit device manufacturing process as set forth in item 28, said conductive film includes at least a Ti film, and the principal face of said semiconductor substrate is selectively oxidized with the hydrogen gas containing steam of such a low concentration that the deterioration of said gate electrodes by the oxidation of said Ti film may be minimized.
31. In a semiconductor integrated circuit device manufacturing process as set forth in item 28, said conductive film includes at least a W film, and the principal face of said semiconductor substrate is selectively oxidized with the hydrogen gas containing steam of such a low concentration as to control the oxidation rate and the oxidized film thickness.
32. In a semiconductor integrated circuit device manufacturing process as set forth in item 28, the conductive film constructing said gate electrodes includes a polycrystalline silicon film, a metal nitride film deposited on said polycrystalline silicon film, and a metal film deposited on said metal nitride film.
33. In a semiconductor integrated circuit device manufacturing process as set forth in item 32, said metal-nitride film is made of WN or TiN, and said metal film is made of W, Mo or Ti.
34. A process for manufacturing a semiconductor integrated circuit device comprises: the step of forming gate electrodes of a MOSFET by depositing a conductive film including at least a metal film over a gate oxide film having a thickness of 5 nm or less and formed over the principal face of a semiconductor substrate and then by patterning said conductive film; the step of improving the profile of the end portions of the side walls of said gate electrodes by oxidizing the principal face of said semiconductor substrate selectively by feeding the hydrogen gas containing steam of such a low concentration, as is generated from hydrogen and oxygen by catalytic action and can control the reproducibility of the oxide film formation and the homogeneity of the oxide film thickness, to the principal face or the vicinity of said semiconductor substrate heated to a predetermined temperature, thereby to oxidize the principal face of said semiconductor substrate selectively; and the step of eliminating the hydrogen, as contained in the oxidized exhaust gas, by causing it to react with oxygen by use of a catalyst.
35. A process for manufacturing a semiconductor integrated circuit device comprises: the step of 25 forming one or more layers of wiring over the principal face of a semiconductor substrate and then depositing a passivation film on the wiring of the uppermost layer; the step of terminating the dangling bonds of Si with hydrogen by heat treating said semiconductor substrate in a gas atmosphere containing hydrogen in the course of or before or after the step of depositing said passivation film; and the step of eliminating the hydrogen, as contained in the heat treated exhaust gas, by causing it to react with oxygen by use of a catalyst.